REACTOR FILAMENT ASSEMBLY WITH ENHANCED MISALIGNMENT TOLERANCE

• US 20150211111A1
• Filed: 01/29/2014
• Published: 07/30/2015
• Est. Priority Date: 01/29/2014
• Status: Active Grant

• Current Assignee: Advanced Material Solutions, LLC
• Original Assignee: GTAT Corporation (ON Semiconductor Corporation)
• Inventors: Rhodes, Aaron D., Ballenger, Keith H.
• Granted Patent: US 10,450,649 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C01B 33/035 by decomposition or reduction of gaseous or vaporised silicon compounds in the presence of heated filaments of silicon, carbon or a refractory metal, e.g. tantalum or tungsten, or in the presence of heated silicon rods on which the formed silicon is deposited, a silicon rod being obtained, e.g. Siemens process
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• CPC Class Codes: C23C 16/4418 Methods for making free-standing articles C23C16/01 takes precedence

Abstract

A tubular filament assembly for a CVD silicon deposition reactor is disclosed that provides consistent, low resistance connections to vertical tubular filaments by forming slidable connections between upper and/or lower ends of the tubular filaments and shaped elements cooperative with the bridge and/or the support chucks, so that the connections are insensitive at least to small variations in tilt angle of the vertical filaments and/or the horizontal bridge. The shaped elements can be incorporated into or separate and cooperative with the bridge and/or the chucks. Various embodiments are described.

Claims

1. A CVD reactor for bulk production of polysilicon, comprising:

a base plate configured with a first filament support chuck and a second filament support chuck;

an enclosure attachable to said base plate so as to form a deposition chamber; and

a filament assembly comprising;

a first tubular silicon filament, said first tubular silicon filament being vertically oriented and having a bottom end making an electrical connection with said first filament support chuck;

a second tubular silicon filament, said second tubular silicon filament being vertically oriented and having a bottom end making an electrical connection with said second filament support chuck;

a horizontal bridge configured for electrically connecting top ends of said first and second tubular silicon filaments; and

a shaped element having a peripheral surface surrounding a central axis of the shaped element, said peripheral surface being slanted or curved so as to form a slidable region of contact around a perimeter of said top end or said bottom end of said first tubular silicon filament when said peripheral surface is placed adjacent to said top end or said bottom end of the first tubular silicon filament;

said peripheral surface being configured to maintain at least 50% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

2. The CVD reactor of claim 1, wherein the first tubular silicon filament has a cross section shaped as a circular annulus.

3. The filament assembly of claim 1, wherein said shaped element is a male element in electrical communication with a first end of said horizontal bridge, said peripheral surface being slanted or curved outward to rest on an inner perimeter of the top of the first tubular silicon filament.

4. The filament assembly of claim 1, wherein said shaped element is a female element in electrical communication with a first end of said horizontal bridge, said peripheral surface being slanted or curved inward to rest on an outer perimeter of the top of the first tubular silicon filament.

5. The CVD reactor of claim 1, wherein said shaped element is a male element in electrical communication with the first filament support chuck, said peripheral surface being slanted or curved outward to rest on an inner perimeter of the bottom of the first tubular silicon filament.

6. The CVD reactor of claim 1, wherein said shaped element is a female element in electrical communication with the first filament support chuck, said peripheral surface being slanted or curved inward to rest on an outer perimeter of the bottom of the first tubular silicon filament.

7. The filament assembly of claim 1, wherein either the top end or the bottom end of the first tubular silicon filament includes a chamfer that is slanted or curved so as to be compatible with the peripheral surface of the shaped element for said slidable region of contact.

8. The CVD reactor of claim 1, wherein the shaped element is incorporated into either the horizontal bridge or the first filament support chuck.

9. The CVD reactor of claim 1 wherein the shaped element is recessed into a lower surface of the first end of the horizontal bridge or an upper surface of the first support chuck.

10. The CVD reactor of claim 1, wherein the peripheral surface of the shaped element is a wall of a groove formed in a lower surface of a first end of the horizontal bridge or an upper surface of the first support chuck.

11. The CVD reactor of claim 1, wherein the shaped element extends either below a lower surface of the horizontal bridge or above an upper surface of the first support chuck.

12. The CVD reactor of claim 1, wherein the peripheral surface is a sloped, substantially flat surface.

13. The CVD reactor of claim 1, wherein the peripheral surface is shaped as a section of a sphere taken perpendicular to a diameter of the sphere

14. The CVD reactor of claim 1, wherein an angle between the peripheral surface and the central axis of the shaped element is approximately 45 degrees.

15. The CVD reactor of claim 1, wherein the first tubular silicon filament has a cross section shaped as a hollow rectangle.

16. The CVD reactor of claim 1, wherein the shaped element includes a separate component, distinct from the filament support chucks and the tubular silicon filaments.

17. The CVD reactor of claim 16, wherein the separate component is in direct physical contact with the horizontal bridge, the first tubular silicon filament, or the first filament support chuck.

18. The CVD reactor of claim 1, wherein said peripheral surface is configured to maintain at least 75% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

19. The CVD reactor of claim 1, wherein said peripheral surface is configured to maintain at least 90% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

28. The CVD reactor of claim 1, wherein said peripheral surface is configured to maintain at least 75% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

29. The CVD reactor of claim 1, wherein said peripheral surface is configured to maintain at least 90% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

20. A filament assembly configured for bulk production of polysilicon in a CVD reactor, said CVD reactor including a base plate configured with a first filament support chuck and a second filament support chuck, said filament assembly comprising:

a first tubular silicon filament, said first tubular silicon filament being vertically oriented and having a bottom end configured to make an electrical connection with said first filament support chuck;

a second tubular silicon filament, said second tubular silicon filament being vertically oriented and having a bottom end configured to make an electrical connection with said second filament support chuck;

a horizontal bridge configured for electrically connecting top ends of said first and second tubular silicon filaments; and

a shaped element proximal to a first end of said horizontal bridge, the shaped element having a peripheral surface surrounding a central axis of the shaped element, said peripheral surface being slanted or curved so as to form a slidable region of contact around a perimeter of said top end of said first tubular silicon filament when said peripheral surface is placed on top of said first tubular silicon filament;

said peripheral surface being configured to maintain at least 50% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

21. The filament assembly of claim 20, wherein the first tubular silicon filament has a cross section shaped as a circular annulus.

22. The filament assembly of claim 20, wherein said shaped element is a male element, said peripheral surface being slanted or curved outward to rest on an inner perimeter of the top of the first tubular silicon filament.

23. The filament assembly of claim 20, wherein said shaped element is a female element, said peripheral surface being slanted or curved inward to rest on an outer perimeter of the top of the first tubular silicon filament.

24. The filament assembly of claim 20, wherein the top end of the first tubular silicon filament includes a perimeter that is slanted or curved so as to be compatible with the peripheral surface of the shaped element for said slidable region of contact.

25. The filament assembly of claim 20, wherein the first tubular silicon filament has a cross section shaped as a hollow rectangle.

26. The filament assembly of claim 20, wherein the inner peripheral surface is shaped as a horizontal, flat annulus.

27. The filament assembly of claim 20, wherein either the male element or the female element includes a separate component, distinct from the tubular silicon filaments and the horizontal bridge.

30. A horizontal filament bridge configured for electrically connecting top ends of a first vertical tubular silicon filament and a second vertical tubular silicon filament in a CVD reactor, said horizontal filament bridge comprising:

a horizontal bridge; and

a shaped element proximal to a first end of the horizontal bridge, the shaped element having a peripheral surface surrounding a central axis of the shaped element, said peripheral surface being slanted or curved so as to form a slidable, region of contact around a perimeter of said top of the first tubular silicon filament when said outer peripheral surface is placed on top of said first tubular silicon filament;

said peripheral surface being configured to maintain at least 50% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

31. The horizontal filament bridge of claim 30, wherein said shaped element is a male element, said peripheral surface being slanted or curved inward to rest on an inner perimeter of the top of the first tubular silicon filament.

32. The horizontal filament bridge of claim 30, wherein said shaped element is a female element, said peripheral surface being slanted or curved inward to rest on an outer perimeter of the top of the first tubular silicon filament.

33. The horizontal filament bridge of claim 30, wherein the shaped element is incorporated into the horizontal bridge.

34. The horizontal filament bridge of claim 30, wherein the shaped element includes a separate component, distinct from the horizontal bridge.

35. The horizontal filament bridge of claim 30, wherein the first tubular silicon filament has a cross section shaped as a circular annulus.

36. The CVD reactor of claim 30, wherein said peripheral surface is configured to maintain at least 75% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

37. The CVD reactor of claim 30, wherein said peripheral surface is configured to maintain at least 90% of said region of contact when an angle between the central axes of the shaped element and a central axis of the first tubular silicon filament is varied up to a maximum tilt angle.